On Saturday 28 March 2009 at 8.30pm, people around the world will turn off their lights for one hour as part of WWF's Earth Hour, to show their support for global action to tackle climate change.
WWF has organised the event as a chance for people to vote for more international action to be taken to tackle global warming. Switching off lights is a vote for Earth, while leaving them on is a vote for global warming.
WWF is urging the world to vote Earth and reach the target of 1 billion votes, which will be presented to world leaders at the Global Climate Change Conference in Copenhagen later this year.
For more information, log onto www.wwf.org.uk/earthhour